摘要：
The pursuit for batteries with high specific energy provokes the research of high-voltage/capacity cathode materials with superior stability and safety as the alternative for lithium iron phosphate. Herein, using the sol-gel method, a lithium vanadium phosphate with higher average discharge voltage (3.8 V, vs. Li~+/Li) was obtained from a single source for Mg~(2+) and Cl~- co-substitution and uniform carbon coating, and a nearly theoretical capacity (130.1 mA h g~(-1)) and outstanding rate performance (25 C) are acquired together with splendid capacity retention (80%) after 650 cycles. This work reveals that the well-sized anion and cation substitution and uniform carbon coating are of both importance to accelerate kinetic performance in the context of nearly undisturbed crystal structure for other analogue materials. It is anticipated that the electrochemistry comprehension will shed light on preparing cathode materials with high energy density in the future.
摘要：
By using pyridinium tribromide as the bromo source, an efficient and practical protocol for the synthesis of C3-brominated imidazo[1,2-a]pyridines through ultrasound-promoted and Na<sub>2</sub>CO<sub>3</sub>-mediated regioselective bromination of imidazo[1,2-a]pyridines has been developed. This method effectively avoids the use of metal catalysts and harsh reaction conditions, and shows attractive characteristics such as operational simplicity, broad substrate scope with good to excellent yields, ease of scale-up and high energy efficiency.
摘要：
MicroRNAs (miRNAs) are involved in a variety of biological processes, and the accurate detection of miRNAs is of great importance for early diagnosis of various cancers. Herein, we have developed a highly sensitive method for the intracellular imaging of miRNAs based on a palindromic probe-induced strand displacement amplification (pSDA). The sensing element is a partly complementary hybrid consisting of two DNA components: one fluorescent dye-labeled signaling probe containing a palindromic sequence and loop-based target recognition site and one quencher moiety-attached locking probe. In the presence of target miRNA, the target species can hybridize with the loop site and release the terminal palindromic fragment, initiating the pSDA reaction. Thus, a considerable amount of fluorescent moieties are spatially separated from the quenchers, generating a dramatically enhanced fluorescence signal. As a result, the target miRNAs can be quantified down to 25 pM with the linear response range over four orders of magnitude. The detection specificity is high enough to eliminate the interference from nontarget miRNAs and other biospecies co-existing in samples, and thus the diseased cells are easily distinguished from healthy cells. Strikingly, the pSDA-based system possesses the desirable capability to discriminate tumor cells from healthy cells, indicating a promising diagnostic tool for the detection of cancers and other diseases in early stage.
摘要：
We report the ductile-brittle transitions and their reliances on specific surface area (gamma), for the bicontinuous and open-cell nanoporous (NP) Cu in tension, using molecular dynamics simulations. With an increase of gamma, NP Cu undergo the first ductile-to-brittle (gamma <= 2.13 nm(-1)) and subsequent brittle-to-ductile (gamma <= 2.13 nm(-1)) transitions. Two different plasticity modes are governing such two ductile-brittle transitions: dislocation activities inhibition for the former and dislocation networks formation contributes to the latter. Serving as the origin of dislocations/stacking faults, the surface characteristic plays a key role in such ductile-brittle transition and deformation modes. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
通讯机构：
[Deng, Guo-Jun] X;[Zhang, Feng] H;Xiangtan Univ, Key Lab Green Organ Synth & Applicat Hunan Prov, Key Lab Environm Friendly Chem & Applicat, Minist Educ,Coll Chem, Xiangtan 411105, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 410128, Peoples R China.
摘要：
A Bronsted acid-promoted sulfuration/annulation reaction for the one-pot synthesis of bis-substituted thiazoles from benzylamines, acetophenones, and sulfur powder has been developed. One C-N bond and multi C-S bonds were selectively formed in one pot. The choice of the Bronsted acid was the key to the high efficiency of this transformation under metal-free conditions.
摘要：
Reworked synthetic polymers (RSPs) are industrial raw materials obtained from waste synthetic polymer (WSP) through physical or chemical means. Different reworked synthetic polymers have different pyrolysis characteristics and synergistic reactions during co-pyrolysis process. The effect of reworked polyamide 6 (PA6), thermoplastic elastomer (TPE), black polypropylene (PP1) and green polypropylene (PP2) co-pyrolysis on the yield and quality of pyrolysis products has been conducted. The results show that co-pyrolysis promotes the degradation of RSPs into more gases. Co-pyrolysis improves the light component of liquid oils and reduces the O content, which is beneficial for liquid fuels. Except for TPE + PP2, co-pyrolysis of RSPs increased di-aromatics, poly-aromatics and aromatic compounds. TPE + PP2 and PP1+PP2 produced high aliphatic compounds including the long chain aliphatic compounds without sufficient degradation, which resulted in the contents of over C-20 were high. In the pyrolysis gases, the relative content of H-2 was increased in all mixed RSPs co-pyrolysis, which can be used as clean fuels. The X-ray diffraction (XRD) analysis shown that new components were found and old components disappeared in co-pyrolysis, indicating chemical reaction had occurred between two different types of RSPs. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved.
作者机构：
[Mai, Yaohua; Qiu, Shudi; He, Wenxin; Guo, Fei; Mai, YH; Guo, F; Hu, Jinlong] Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China.;[Peng, Chang; You, Jiang] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Liu, Xianhu; Li, Chaohui] Zhengzhou Univ, Natl Engn Res Ctr Adv Polymer Proc Technol, Zhengzhou 450002, Henan, Peoples R China.
通讯机构：
[Mai, YH; Guo, F] J;[Peng, Chang] H;Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
关键词：
energy-level alignments;hole-transport materials;inverted solar cells;polyfluorene copolymers
摘要：
Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention due to their cost-effective production. Hole-transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. Herein, three polyfluorene copolymers (TFB, PFB, and PFO) are investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Due to its high mobility along with the favored energy-level alignment with perovskite, TFB shows superior charge extraction and suppressed interfacial recombination than PFB- and PFO-based devices, which delivers a high efficiency of 18.48% with an open-circuit voltage (V-OC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO-based devices results in substantial losses in both V-OC and photocurrent. These results demonstrate that TFB can serve as a superior HTM for inverted PSCs. Moreover, it is anticipated that the performance of the three HTMs identified here might guide the molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.
